Method for producing titanium metal



Oct. 7, 1958 E.'J.-DUNN METHOD FOR PRODUCING TITANIUM METAL Original Filed April 23. 1954 INVENTOR. cl w ar' cf T-T- Dunn United States .atent O Original application April '23, 1954, Serial No. 425,341.

Divided and this application November 14,1956, Serial No. 626,790

3 Claims. c1."1-'17-10o I v (Granted under Title 35, U. (S. Code (1952), see. 266) The invention described herein :may be manufactured and usedby or for the Government for governmental purposes without the payment tome of any royalty thereon. This invention relates to the production of titanium metal and appertaius to an improved apparatus and method of the type disclosed in the pending United States patent application, Serial No. 329,939 of Manual GoldmanandArthur E. Jones, filed on January 6, 1953, now abandoned. This application is a division of application Serial No. 425,341, filed April- 23, 1954. Titanium .metal due to its advantageous characteristics has many useful purposes at present and could potentially serve ,many more due to its desirable characteristics of lightness, strength, corrosion resistance, low coeflicient of expansion, and surface hardening properties. This metal possesses advantages over the combined characteristics of steel and aluminum without the disadvantages of density of the former and the relatively low strength and low-corrosion resistance of the latter.

The utilization of titanium on a larger scale commercially is hindered to a large extent only -by the lack-of more economical and more productive methods. hindrance is .due mainly to the ready contamination of titanium by oxygen, nitrogen, carbon and other atmospheric reacting elements with which the titanium comes in :contact during refining of this metal. Accordingly, it

This

is an object of this invention to provide a method and apparatus for producing substantially pure titanium metal in an atmosphere substantially free of contaminating gases and :in a manner more economical and more ex: peditious than by heretofore known methods and in quantities sufiicient for large scale commercial use. The method and apparatus of the invention is adapted to the production of titanium by both the batch and continuous method. t

It ,is another object of this invention to provide a method of producing metallic titanium by the thermal d'ecomposition of a volatized titanium halide without the disadvantage of having the metal adhere to or deposit on the furnace wall with the subsequent necessity-of cutting .or stripping the metal from the'wall.

A more particular object of this invention is to provide means for cooling the wall of an inductively heated dissociating furnace to a temperature below that at which thermal decomposition of titanium tetraiodide occurs while inductively heating the metal particles within the furnace to the decomposition temperature of the halide and thereby provide a surface at a proper temperature on the particles upon which titanium metal will deposit. This furnace may be operated at a reduced pressure or at a slightpositive pressure.

A vfurther object of this invention is to provide a pluseem e 1958 2 rality of dissociating furnaces arranged in parallel to permit the evacuation'of the deposited titanium from each of-the furnaces during the batch method without interrupting the continuous production of metal in the other furnaces. I

A still further object of this invention :resides in the provision of an inclined dissociating furnace so .constructcd as to permit the continuous production of titanium metal by thermal decomposition and removal of the metal without interruption in operation of the furnace.

Other objects and advantages of the invention will be apparent during the course of the following description.

The invention will be more fully described in the following description taken in connection with the accompanying drawing forming a part hereof and in which:

Fig. 1 illustrates, in a conventional and diagrammatic mannen'an apparatus embodying the invention, showing one of the vacuum dissociating furnaces in detail in vertical section. I

Fig; 2 is a sectional view of aipor'tion of a modified form of the invention showing an arrangement of an inclined rotary dissociating ,fu rnace.

In the apparatus according to this invention, after the evacuation of air or other gases which may be present in the dissociating furnace, ztitanium halide, preferably titanium tetraiOdide is admitted into the furnace. The titanium halide for use in the dissociating furnace may be produced by any of various well known methods, as for example in obtaining titanium tetraiodide a charge of crude titanium such as ilmenite or rutile, preferably in powdered form, is placed into ahopper, pure iodine in the solid state added thereto, and the charge is subjected to heat. The various titanium iodides resulting from this reaction are than fractionated to withdraw the vaporous tetraiodide which is used in the dissociating furnace.

In the dissociating furnace, upon the thermal decomposition of the titanium halide to titanium metal, the free metal accumulates on the surface of particles of titanium, tungsten or other suitable material which has been introduced into the furnace for this purpose. metal deposited on such particles is removed periodically from the furnace. The halide gas liberated by the decomposition is withdrawn from the furnace and is condensed and recirculated for reuse by conventional apparatus.

The decomposition of the tetraiodide, according to the invention, may be carried out in a single furnace, or in a plurality of furnaces supplied with titanium halide from a common source and arranged in parallel .relation and so that the individualfurnaces may be selectivelydisconnected and unloaded without interfering with the operation of theremaining furnaces.

I An inclined furnace having a substantially greater length to provide a considerably longer deposition period for the metal, may be used; and an atmosphere sealing valve arrangement provided at the outlet, permits the continuous refining and removal of titanium from the Z apparatus without the ingress of contaminating elements into the systems In the apparatus shown in Fig. 1, described 'incon nection with the production of titanium metal from titan- -ium.tetraiodide, air and other contaminating gases are removed from the system by means of a conventional such as the gas burners 11, may be utilized to supply heat The titanium 32- anda hinged lower portion upper halfby fasteners 46.

- In order to maintain the wall temperatureof thedissociating furnace 2.4 below. that at which titanium will 2,855,331. r o .o

.to a temperature of approximately Ct -which affords substantially: complete reaction. of the charge into titanium iodides. .CheckyalveslZ on either side of thereactor 8 and a globe valve 14. permit isolation of the re actor-from the rest of the-system during replenishment -.ofthecharge.,. o e m-- The mixture of the various titanium iodides produced:

in the reactor flow. tothe fractionating colum 16' wherein .only the tetraiodide is permitted topass -throughthe piping:18 and valves 20 and22 to-the dissociating yac 'uum furnaces 24. The residual iodides arere'turned to' mthe reactor 8 by conventional meanstnot shown)! In the arrangement shown, the dissociation furnace to-which I this invention :is. particularly'directed, is constructed of ceramic or other suitable substantially non-conductible material and -is arrangedto rotate on bearings 26 concentrically positioned around; the tetraiodide inletztt and over; the liberatediodine outlet-30, and is driven by a.

conventional-motor 32 andgcaringarrangementziid. One

end of: the: furnace is appropriately sealed at 2,6 with aremovable :endclosure -38 to permitremoval of the titanium metal product when the furnace is: isolated and. disconnected from the system by means of valves 20 and 21 and adapters 23.

. Annularly disposed around the furnace24is a conventional watercooledinduction coil 40, suitably-connected to an electric source at42, to supply the requisite-decomposition temperature of ap roxi 4 r vapors from being drawninto' pumps 2 and 4,conven-' tional :cold traps 54 may -rangemen-t for the receptacle into: which the furnace outlet leads. The. inclined'dissociating furnace 60, pro 'vided with. similar means for heating, 3 cooling, evacuating and: driving means asthose'previously described, may be mately1200" C. in the titanium or other metallic particles which have been introduced into the ,furnace'for the purpose of having titanium'cleposit thereon.- l

- Completely; surrounding the furnace 24 and induction coil 40 is af urnace jacket 44 shown in twoequal half por tions, a fixedupper half. upon which is secured-the motor suitably closed to the adhcreto the wall 25 of the furnace; it may be necessary I to supply cooling means in addition to that furnished by '40 that of. the. water circulating; through the induction coils 40. For this purpose'apertures 48' are provided in the upper fixed semi-cylindrical half of the jacket 44 to permit exit of cooling air introduced into the annular space 47 by nozzles (not shown) connected to the air inlet valve 43. It will be understood that other means, such as water circulating within the wall of the furnace 24 in any conventional manner may be used to provide the adtional Wall cooling means. 7

In order that some means he provided for collecting the titanium metal which is freed during the thermal decomposition of the titanium halide, particles of suitable material, such as titanium or tungsten are introduced into the furnace. Where a rotating furnace is used, bafiles (not shown) may be used on the wallet the furnace to tumble the particles to assist in the deposition of titanium on the surface of the particles. When a non-rotating furnace is used the material in the form of filament 1.

posited on the material introduced for this purpose, the.

furnace is isolated by closing valves- 20 and 21, removing end closures 45 of the jacket and 38 of the-furnace, and withdrawing the titanium from the furnace. To place the furnace back into operation the reverse procedureis folmethod and apparatus of this invention. I 1 t made longer in length than that. of the horizontal type;

I in order to permit alonger periodduring-which titanium can deposit entire surface of particles which are thensubs equently-discharged into the outlet-62' through the open ings 264inthc rotating furnaces A conventional sealing:

ring -66 positioned over the outlet openings-64 prevents t :access ofair into. the furnace. 1 In order to prevent'air from entering frorri the outlet receiver 68, a systcm such as. valves :70 and 'l'l'maybe utilizedto close offthcre I ceiver 68.= In operation valves 70 are closed and the-re- ,ceiver 68 'isevaeuated; this may be accomplished by pipe connection ,(not, shown) between the receiver 68 and the freed iodine yacuum-outletl'n. Until thereceivcr has been cleared ,of air, titaniuml'accumulatcs at outlet 62. t 1 Valve 70 is then opened the product permitted-to accumulate in thereceiver 68. The valve 70 is then closed and the product'removed from the receiver 63 through valve 71 Whichis then closed, the receiver 68 is and. theoutlet cyclerepeatedas stated; Of course, it' will be understoodthat although: the 'titanium t'etraiodide has been mentioned as the preferred composition to housed in. the production of titaniummetal; :other. titanium halides may be employed in the From' the foregoing, it is apparent thatI have devised q a novel. method and apparatus embodying the features and advantages stated in the above description. I It is to be i understood that the invention is. susceptible, of various I i modifications without departing from the spirit or. scope of the invention. t

What is claimed is:

1. The method of obtaining titanium metal from a titanium halide which comprises flowing a titanium halide through a dissociating furnace having an atmosphere substantially free from contaminating gases and having the wall of the furnace at a temperature below that at which titanium halide will decompose and deposit on said wall, introducing metallic material insaid furnace upon which the metal dissociated from the titanium. halide will deposit, maintaining said metallic material in substantially continuous motion, inducing heat to a halide decomposing temperature of approximately. 1200 C. in said metallic material and withdrawing the titanium metal and liberated halide gas from the furnace. i

2. Themethod of obtaining titanium metal from titanium tetraiodide which comprises flowing titanium tetraiodide through a dissociating furnace having an atmosphere substantially free from contaminating gases, introducing metallic particles into said furnace and maintaining said particles in substantially continuous motion,

' I. inductively heating said particles to a temperature of approximately 1200 C. for decomposing said titanium tetraiodide, maintaining the walls of said furnace at a temperature below thedecomposition temperature of titanium tetraiodide, and withdrawing the gaseous and solid reactants from said furnace.

lowed, allowing a sufficient interim between opening of valves 21 and 20 to permit evacuation andheating of the furnace contents prior to admitting titanium halide. 'lhe liberated gaseous halide together with the titanium halide which has not been decomposedlis drawn through piping 50 to the condenser 52 wherein the gases are liquilied and returned to reactor 8. To prevent corrosive 3. The method of continuously obtaining titanium metal from a titanium halide which comprises continuously flowing a titanium halide through a dissociating furnace having an atmosphere substantially free from contaminants, introducing into said furnate discrete particles of metallic material on which titanium will deposit and moving said particles continuously through said furnace, inductively heating said particles in said furnace to the invention whichevacuated,

References Cited in the file of this patent UNITED STATES PATENTS 1,759,661 Muller et a1. May 20, 1930 10 Van Arkel et a1 Dec. 13, 1932 Lander July 1, 1952 Loonam Nov. 16, 1954 Nack et a1. Jan. 17, 1956 .Gross Aug. 28, 1956 FOREIGN PATENTS Great Britain Oct. 14, 1953 

1. THE METHOD OF OBTAINING TITANIUM METAL FROM A TITANIUM HALIDE WHICH COMPRISES FLOWING A TITANIUM HALIDE THROUGH A DISSOCIATING FURNACE HAVING AN ATMOSPHERE SUBSTANTIALLY FREE FROM CONTAMINATING GASES AND HAVING THE WALL OF THE FURNACE AT A TEMPERATURE BELOW THAT AT WHICH TITANIUM HALIDE WILL DECOMPOSE AND DEPOSIT ON SAID WALL, INTRODUCING METALLIC MATERIAL IN SAID FURNACE UPON WHICH THE METAL DISSOCIATED FROM THE TITANIUM HALIDE WILL DEPOSIT, MAINTAINING SAID METALLIC MATERIAL IN SUBSTANTIALLY CONTINUOUS MOTION, INDUCING HEAT TO A HALIDE DECOMPOSING TEMPERATURE OF APPROXIMATELY 1200*C. IN SAID METALLIC MATERIAL AND WITHDRAWING THE TITANIUM METAL AND LIBERATED HALIDE GAS FROM THE FURNACE. 